This invention relates to unsaturated polyester resins and particularly to unsaturated polyester resin formulations including significant amounts of both dicyclopentadiene and certain "dimer acids" which are more fully defined herein.
Many approaches have been employed to impart flexibility to unsaturated polyester resin formulations. For example, it is known to employ adipic acid in addition to or as a partial substitute for the commonly used phthalic or isophthalic acid, and that the adipic acid will result in enhanced resiliency for the finished product.
I am also aware that the particular dimeric and trimeric acids which I use in my invention have been used in unsaturated polyester resins--see page 9 of the 1979 Emery Industries Bulletin on "Empol" dimer and trimer additives, a copy of which is provided with the Prior Art Statement herewith; see also U.S. Pat. No. 3,674,727.
The use of dicyclopentadiene in unsaturated polyeser resin formulations has also increased considerably in recent years. See, for example, U.S. Pat. Nos. 4,029,848; 4,148,765; 4,233,432, and 4,246,367. DCPD, as it will hereafter be called, is not known, however, for its use in formulations designed for resiliency or flexibility.